Relation of epidermal growth factor receptor expression to goblet cell hyperplasia in nasal polyps

BACKGROUND: Because the epidermal growth factor receptor (EGFR) system regulates mucin production in airway epithelium, we hypothesized a role for this system in mucus hypersecretion that occurs in nasal polyposis. OBJECTIVE: We examined the relationship between goblet cell hyperplasia, EGFR expression, and inflammatory mediators produced by eosinophils and neutrophils in nasal polyp tissues. METHODS: Nasal polyp tissue samples from 8 patients and nasal turbinate biopsy specimens from 6 normal control subjects were examined for alcian blue/PAS staining, mucin MUC5AC (MUC5AC), and EGFR immunoreactivity and EGFR gene expression (in situ hybridization). We also examined the role of eosinophils and neutrophils in goblet cell hyperplasia. RESULTS: In control nasal mucosa alcian blue/periodic acid-Schiff- and MUC5AC-stained areas were 18.40% +/- 1.31% and 21.89% +/- 1.43%, respectively. In polyps the alcian blue/periodic acid-Schiff- and MUC5AC-stained areas were 51.30% +/- 5.85% and 52.07% +/- 6.58%, which was significantly larger than that found in control subjects (each comparison, P <.01). Four of 6 control specimens expressed EGFR messenger RNA and protein weakly in the epithelium. In polyps 4 of 8 specimens expressed EGFR gene and EGFR protein strongly; the EGFR-stained area was greater in hyperplastic than in pseudostratified epithelium. TNF-alpha immunoreactivity, expressed in eosinophils, was increased in EGFR-positive polyps compared with EGFR-negative polyps, suggesting a role for TNF-alpha in EGFR expression. Neutrophils were increased in the epithelium of EGFR-positive compared with EGFR-negative polyps, suggesting a role for these cells in mucin expression and in goblet cell degranulation. CONCLUSION: These data suggest a role for EGFR cascade in the regulation of goblet cell mucins in nasal polyps. Proof of concept will require clinical studies using selective EGFR inhibitors.     

Immunohistochemistry of the cytoskeleton of human prostatic epithelium. Evidence for disturbed organization in neoplasia.

An indirect immunoperoxidase technique was used to evaluate keratin, actin, tubulin, and calmodulin immunoreactivity in histologic sections of normal, hyperplastic, and neoplastic human prostate. Polyclonal as well as monoclonal keratin antibodies produced equivalent and intense staining of normal epithelium. The immunoreactivity of normal prostate with keratin antibodies was more pronounced than with antibodies to the other components of the cytoskeleton. Variation in staining for components of the cytoskeleton was minimal. The same findings applied to hyperplastic prostate. The immunoreactivity of prostate tumors with antibodies to these cytoskeletal proteins differed markedly from normal prostate. Prostatic carcinomas showed reduced keratin immunoreactivity with a panepithelial antibody, but unaltered or enhanced immunoreactivity with tubulin, actin, and calmodulin antibodies. Many tumors were unreactive with a monoclonal keratin antibody that was strongly reactive with tissues that contained cytokeratin 18 (45-kd) and which intensely stained normal and hyperplastic prostate. In addition, prostate carcinomas often yielded heterogeneous patterns of staining with actin, tubulin, and calmodulin antibodies in contrast to normal and hyperplastic prostate, which showed uniform staining. The results suggest that a disturbance in the organization of the cytoskeleton may accompany neoplastic transformation of human prostate.     

Macrophage infiltration is associated with VEGF and EGFR expression in breast cancer

Angiogenesis is esential for tumour growth and metastasis. Vascular endothelial growth factor (VEGF) is a potent endothelial cell mitogen and is an important component of the angiogenic stimulus in a range of human neoplasias. In addition to its mitogenic activities, VEGF has also been found to stimulate migration in macrophages via the flt-1 VEGF receptor. It has previously been shown that increased focal tumour macrophage infiltration is associated with increased angiogenesis and worsened relapse-free and overall survival in breast cancer. Macrophages are able to stimulate angiogenesis by their production of a range of factors including VEGF, tumour necrosis factor-alpha (TNF-alpha), and thymidine phosphorylase (TP). Thus, in breast cancer, VEGF could have a dual role in the regulation of angiogenesis, by direct mitogenic stimulation of endothelial cells, and also indirectly by attracting macrophages into avascular tumours. The purpose of this study was to localize VEGF protein in a series of 96 consecutive primary breast carcinomas and to determine its relationship to focal macrophage infiltration (macrophage index). These two variables were also compared with the pathological features of the tumours, as well as oestrogen receptor (ER), epidermal growth factor receptor (EGFR), microvessel density, macrophage index, and survival. An inverse relationship (p=0.0006) was noted between VEGF and EGFR, with high VEGF expression correlating with low EGFR levels. In the EGFR-negative group of cases (n=56), positive associations were observed between VEGF expression and macrophage index (p=0.005), ER (p=0.05), p53 (p=0. 006), tumour grade (p=0.02), and tumour necrosis (p=0.03). Macrophage counts were higher in EGFR-positive tumours (p=0.0006) and no associations were found between VEGF expression and increased microvessel density. These results show that in breast cancers there are two types of macrophage infiltrates, one associated with the presence of EGFR and low VEGF expression in tumours and the other with high VEGF expression in EGFR-negative tumours. VEGF expression may be an important factor in the recruitment of tumour-associated macrophages into breast carcinomas and may thus have an additional, indirect, pathway of angiogenic stimulation in this type of tumour.     

Alpha-methylacyl coenzyme A racemase immunoreactivity in partial atrophy of the prostate

It was reported that 15 of 19 consultation cases of prostatic partial atrophy were a-methylacyl coenzyme A racemase (AMACR)-positive. We investigated partial atrophy cases from a single institution using a standard AMACR immunostaining method. Immunohistochemical analysis was performed using an antibody cocktail containing p63, high-molecular-weight keratin (34bE12), and AMACR antibodies on 122 foci of partial atrophy. AMACR staining was analyzed in partial atrophy (n = 122) and compared with adjacent benign glands (n = 122) and prostatic carcinomas (n = 28). Of 122 foci of partial atrophy, 38 (31.1%) showed AMACR immunoreactivity. Typically, AMACR staining was weak or moderate. In addition, 82 (67.2%) showed patchy to negative distribution of basal cells. Partial atrophy may show AMACR immunoreactivity when using a 34bE12, p63, and AMACR antibody cocktail staining method. Compounding this problem, focal lack of basal cells may be seen. However, the AMACR staining pattern of partial atrophy is usually comparable to that of adjacent benign glands and substantially different from adenocarcinoma.     

Expression of ras oncogene p21 antigen in normal and proliferative thyroid tissues.

The ras oncogene p21 antigen (p21) has been identified in several epithelial malignancies, including breast, colon, bladder, and prostate. The pattern and intensity of immunoreactivity between normal and neoplastic tissues has been distinctly different. The authors examined thyroid lesions from 73 different cases by immunohistochemistry for the expression of p21 with a monoclonal antibody (RAP-5). Normal thyroid tissues (4) showed the least immunoreactivity, while papillary carcinomas (8), Hurthle cell carcinomas (10), and follicular carcinomas as (3) showed slightly more intense staining than Hurthle cell adenomas (12) or follicular adenomas (9). Anaplastic carcinomas (4) showed much less intense staining than most other carcinomas, while medullary thyroid carcinomas (5) showed only slight immunoreactivity. Inflammatory thyroid lesions associated with goiters, including Hashimoto's thyroiditis (6) and Graves' disease (8), showed moderate to intense expression of p21 as did multinodular goiters (4). Semiquantitative analysis of staining intensity by serial dilution of the primary antibody showed significant differences in staining between normal thyroid and some carcinomas (P less than 0.05), but not between carcinomas and adenomas. These results show that while antibody RAP-5 detects an antigen that is only weakly expressed in normal thyroids, this antigen is more strongly expressed in benign and malignant thyroid tumors, as well as in inflammatory and nonneoplastic proliferative thyroid lesions. It is thus not helpful in identifying differences between neoplastic and non-neoplastic thyroid lesions.     

Diagnostic utility of p75 neurotrophin receptor (p75NTR) as a marker of breast myoepithelial cells.

We evaluated the low affinity neurotrophin receptor (p75NTR) as a marker of breast myoepithelial cells. Immunohistochemical staining for p75NTR was performed on paraffin sections of 122 malignant breast lesions, 28 benign lesions and the adjacent normal breast tissue. The staining pattern was compared to those of myosin heavy chain and p63. p75NTR immunostain was consistently positive and compatible with p63 and myosin immunoreactivity in the myoepithelial cells of the normal mammary gland, benign breast lesions (six usual ductal hyperplasias, six specimens with sclerosing adenosis, eight intraductal papillomas, six fibroadenomas), and carcinoma in situ (18 ductal carcinomas in situ, two noninvasive papillary carcinomas, two lobular carcinomas in situ). The luminal cells were negative for p75NTR, but rare positive cells were noticed in the solid areas of some of the usual ductal hyperplasias. Four of 64 invasive ductal carcinomas (6%) and all metaplastic carcinomas (n = 3, 100%) showed a variable degree of p75(NTR) positivity. No p75NTR expression was found in the malignant cells in all in situ carcinomas, invasive lobular carcinomas (n = 11), tubular carcinomas (n = 10), invasive papillary carcinomas (n = 6), mucinous carcinomas (n = 4), and medullary carcinomas (n = 2). No myosin immunoreactivity was seen in the luminal/tumor cells, but p63 pattern of staining in the luminal/tumor cells was quite similar to that of p75NTR. Although significant p75NTR immunoreactivity was noticed in the vessels, nerves, and stromal component of fibroadenomas, no difficulties in the evaluation of the immunostain of myoepithelial cells were encountered. Our study shows that p75NTR is a useful marker for breast myoepithelial cells and can be used to rule out invasive disease as well as to evaluate difficult for diagnosis sclerosing lesions. Our data suggest a role of neurotrophins in the development of fibroepithelial breast tumors and some of the breast carcinomas.     

Expression of the retinoblastoma-related gene Rb2/p130 is downregulated in atypical endometrial hyperplasia and adenocarcinoma

The retinoblastoma-related gene Rb2/p130 encodes a protein that is a negative cell-cycle regulator normally expressed in a number of adult tissues. This protein shares many structural and functional features with the product of the retinoblastoma gene, one of the best-studied tumor-suppressor genes, and plays a fundamental role in growth control. The Rb2/p130 gene product associates with specific members of the E2F family and various cyclins, displaying a growth-suppressive activity specific for the G(0)/G(1) phases. It has been reported that Rb2/p130 is involved in the pathogenesis and progression of lung cancer and mesothelioma. We previously demonstrated for the first time that reduced immunohistochemical expression of Rb2/p130 was a strong independent predictor of poor outcome in endometrial cancer. The aim of the present study was to evaluate Rb2/p130 expression in normal, hyperplastic, and neoplastic endometrial lesions to determine whether the protein plays a significant role in endometrial carcinogenesis. We evaluated Rb2/p130 expression by immunohistochemistry staining in 102 specimens chosen to represent a spectrum of endometrial changes, including proliferative endometrium (n = 18), secretory endometrium (n = 18), simple or complex hyperplasia without atypia (n = 18), atypical hyperplasia (n = 18), and invasive carcinoma (n = 30). We found that Rb2/p130 was highly expressed in proliferative endometrium and in hyperplasia without atypia, the mean percentage of stained nuclei being 66% and 60%, respectively, but was downregulated in secretory endometrium, atypical hyperplasia, and carcinoma, with mean scores of 38%, 25%, and 22%, respectively. When categorized on a semiquantitative scale (negative v 1% to 50% v >50% positivity), endometrial cancer displayed significantly less staining than all other endometrial samples (P <.001). Poorly differentiated carcinomas (n = 9) showed a significantly lower immunoreactivity for Rb2/p130 than did well-differentiated carcinomas (n = 11; P =.005) and moderately differentiated carcinomas (n = 10; P =.03). In addition, atypical hyperplasia showed a significantly lower immunoreactivity than either proliferative endometrium (P =.003) or hyperplasia without atypia (P = 0.02). Our findings of a progressive decrease in Rb2/p130 expression from hyperplastic endometrium through atypical hyperplasia to poorly differentiated carcinomas suggest the involvement of this negative cell-cycle regulator in endometrial carcinogenesis. Furthermore, immunostaining for Rb2/p130 may prove diagnostically useful in the often difficult distinction between hyperplastic and atypical hyperplastic endometrium. HUM PATHOL 32:360-367.     

Expression of Simple Mucin Type Antigens and Lewis Type 1 and Type 2 Chain Antigens in the Thyroid Gland: An Immunohistochemical Study of Normal Thyroid Tissues,Benign Lesions,and Malignant Tumors

In order to characterize the pattern of expression of carbohydrate structures in several types of thyroid tissues and to evaluate the putative usefulness of the detection of such antigens in diagnostic surgical pathology, we undertook the immunohistochemical study of simple mucin type antigens (T, Tn, and sialyl Tn), Lewis type I antigens (Lewis a, sialyl Lewis a, and Lewis b), and Lewis type 2 related antigens (precursor type 2, H type 2, Lewis x, sialyl Lewis x, and Lewis y) in thyroid samples obtained from 65 patients. The material consisted on paraffin sections of normal thyroid (n = 43), benign lesions (13 goiters/ hyperplastic lesions and 15 adenomas), and malignant tumors (12 follicular carcinomas and 27 papillary carcinomas, 5 of which had lymph node metastases) of the thyroid follicular epithelium. Tn, T, and precursor type 2 antigens were the only antigens that were detected—and very rarely—in normal thyroid. Benign lesions were similar to normal thyroid despite displaying a higher prevalence of immunoreactivity for severa antigens of the three groups. Thyroid carcinomas presented a significantly higher level of expression of all types of simple mucin, Lewis type 1, and Lewis type 2 antigens than the normal thyroid and benign lesions. The expression of sialyl Tn was restricted to malignant tumors, and the expression of sialyl Lewis x was closely associated, though not exclusively, to papillary carcinomas. The immunoreactivity was stronger and the number of positive cases was higher in papillary than in follicular carcinomas. No differences were found between primary tumors and the respective metastases. The existence of distinct patterns of expression of carbohydrate antigens in different types of thyroid lesions points to the usefulness of the detection of some of these antigens in thyroid surgical pathology. The putative role of such antigens in the peculiar metastatic properties of thyroid carcinomas remains unsettled.     

Stathmin Expression in Pheochromocytomas,Paragangliomas, and in other Endocrine Tumors

Pheochromocytomas are neuroendocrine tumors confined to the adrenal glands, and malignant pheochromocytomas can spread to various sites including the liver, lung, and bones. Paragangliomas occur in numerous locations in the body, so assessment of metastatic disease is more challenging, as patients with familial syndromes often have multiple, possibly independent paragangliomas. The most reliable criterion for malignancy in pheochromocytomas and paragangliomas is metastatic disease. Because there are few immunohistochemical markers that are useful in the diagnosis of malignancy in pheochromocytomas and paragangliomas before they metastasize, more markers are needed to characterize these tumors. Stathmin is a widely expressed 17-kDa cytoplasmic, microtubule destabilizing and sequestering phosphoprotein that is important in cell motility and cancer cell metastasis. It is upregulated in various malignancies. We examined stathmin expression in tissues from patients with pheochromocytomas (n = 48), malignant pheochromocytomas (n = 28), paragangliomas (n = 42), and malignant paragangliomas (n = 21) by immunohistochemistry using tissue microarrays (TMA) with a polyclonal antibody against stathmin. A series of other endocrine tissues and tumors (n = 70) were also examined for stathmin expression. Stathmin was more highly expressed in pheochromocytomas compared to normal adrenals, a finding confirmed by Western blot. There was higher expression of stathmin by immunohistochemical staining in malignant pheochromocytomas compared to pheochromocytomas without metastasis when analyzed by maximal staining (p = 0.012). Stathmin was present in a wide variety of endocrine tumors and was most highly expressed in rapidly proliferating tumors including anaplastic thyroid carcinomas, Merkel cell carcinomas of the skin and small cell carcinomas of the lung. These results show that stathmin is expressed at higher levels in more rapidly proliferating endocrine tumors. However, it is probably not useful as a stand-alone marker to determine malignancy in pheochromocytomas for individual tumors.     

neu oncogene protein and epidermal growth factor receptor are independently expressed in benign and malignant breast tissues

The neu oncogene protein, p185, and epidermal growth factor receptor (EGFR) were localized immunohistochemically in benign and malignant human breast tissues using monoclonal antibodies. Both benign and malignant epithelial cells were positive for these oncogene proteins in acetone-postfixed frozen sections. Stromal cells were negative for p185, but occasionally positive for EGFR. Myoepithelial cells were consistently positive for EGFR, and p185 was localized predominantly in duct-lining cells, where the basolateral plasma membrane was the normal expression site of both substances. Paraformaldehyde-prefixed frozen sections were less sensitive for antigen demonstration. Based on the intensity of immunoreactivity, 11 of 37 acetone-postfixed breast carcinomas (30%) were judged neu overexpressors, while none of 24 benign tissues overexpressed neu. Epidermal growth factor receptor was demonstrated in 18 of 36 acetone-postfixed cancer tissues (50%) and was overexpressed in three (8%). At the cellular level, heterogenous expression of p185 and EGFR was occasionally observed in both benign and malignant tissues, and a single case of cancer overexpressing both neu and EGFR showed reciprocal patterns of staining, indicating their independent expression. In some carcinomas, EGFR was localized only in stromal cells. Our findings confirmed mutually independent expression of the two closely related protooncogenes in benign and malignant breast tissues.     

Expression of c-erbB-2 protein and epidermal growth factor receptor in normal tissues of the female genital tract and in the placenta

Summary The c-erbB-2 (HER-2/neu) protein is a membrane glycoprotein growth factor receptor that has molecular homology with the epidermal growth factor receptor (EGFR). To investigate the relationship between the expression of c-erbB-2 protein and EGFR in the tissues of the human female genital tract and in the placenta, we examined the immunohistochemical reactivity of monoclonal antibodies against both of these proteins. In the müllerian-derived genital tract, epithelial cells of the fallopian tube, endometrium, and endocervix showed reactivity for c-erbB-2 protein, whereas reactivity for EGFR was distributed mainly in the stromal cells throughout the menstrual cycle and during pregnancy. In addition, the staining intensity for EGFR in the endometrial stroma increased with its decidualization. In the exocervical squamous epithelium, basal cells were cerbB-2 protein-negative and EGFR-positive, but the more differentiated squamous cells of the intermediate layer were c-erbB-2 protein-positive and EGFR-negative. In the placental tissues, cytotrophoblasts and syncytiotrophoblasts of the chorionic villi were c-erbB-2 protein-negative and EGFR-positive. In contrast, intermediate trophoblasts in the extravillous space were c-erbB-2 protein-positive and EGFR-negative. Thus, there is an inverse relationship between the expression of c-erbB-2 protein and EGFR in the tissues of the female genital tract and in the placenta. This suggests that there may be a regulatory mechanism(s) for the expression of both proteins that is associated with the differentiation and/or function of cells in the female genital tract and the placenta.     

Immunohistochemical staining of normal, hyperplastic, and neoplastic adrenal cortex with a monoclonal antibody against alpha inhibin.

AIMS: To investigate the immunohisto-chemical staining of normal, hyperplastic, and neoplastic adrenal cortex with a monoclonal antibody against alpha inhibin. Also, to determine whether immunostaining with this antibody is useful in differentiating between adrenal cortical neoplasms and other tumours involving the adrenal gland that might mimic them. METHODS: Normal adrenal tissue (n = 20) and specimens from cases of adrenal hyperplasia (n = 13), adrenal cortical adenoma (n = 15), adrenal cortical carcinoma (n = 4), phaeochromocytoma (n = 8), and adrenal metastatic tumour (n = 7) were stained with a monoclonal antibody against the alpha subunit of human inhibin. RESULTS: Positive staining with the anti-alpha inhibin monoclonal antibody was seen in all normal adrenal glands. Immunoreactivity was largely confined to the inner cell layers of the adrenal cortex, with no staining of the adrenal medulla. All hyperplastic adrenal glands and adrenal cortical adenomas and carcinomas were also immunoreactive. The other tumours studied were negative. CONCLUSIONS: There is consistent immunoreactivity with the anti-alpha inhibin monoclonal antibody in normal adrenal cortex and in hyperplastic and neoplastic adrenal cortical lesions. In the normal adrenal cortex, positive staining is mainly confined to the zona reticularis. Other neoplasms involving the adrenal gland are negative. Immunohistochemical staining with anti-alpha inhibin monoclonal antibody, performed as part of a panel, may prove to be of value in the distinction between adrenal cortical carcinoma and phaeochromocytoma or metastatic tumour.     

Aberrant p27kip1 expression in endocrine and other tumors.

The p27kip1 (p27) gene encodes an inhibitor of cyclin-dependent kinase activity. The expression of p27 protein in normal and neoplastic tissues was investigated by immunoblotting and immunohistochemistry. Immunoblotting studies detected a 27-kd protein band that was decreased in neoplastic pituitary tissues compared with normal pituitary. Immunostaining of 177 tissues showed abundant expression of p27 protein in normal tissues with decreased numbers of immunoreactive cells in adenomas and carcinomas in both endocrine and nonendocrine tissues. p27 expression was inversely related to the proliferation marker Ki-67 antigen detected with monoclonal antibody MIB-1. Parathyroid adenomas and hyperplasias had similar Ki-67 labeling indices; however, hyperplasias had threefold more p27-positive cells than parathyroid adenomas, suggesting that p27 immunostaining may be useful in distinguishing between these two conditions. These results indicate that there is widespread aberrant p27 expression in hyperplastic tissues and in benign and malignant neoplasms compared with normal tissues. Immunohistochemical analysis of p27 along with Ki-67 may be used to assess the biological behavior of various neoplasms, to classify hyperplastic and neoplastic tissues, and to study cell cycle regulation during tumor progression.     

Secretogranin IV immunoreactivity in medullary thyroid carcinoma: An immunohistochemical study of 62 cases

The presence and intracellular distribution of secretogranin IV (Sg IV) was determined on light microcop by the avidin-biotin peroxidase complex method with the monoclonal antibody (mAb) Hisl-19 in normal and hyperplastic C-cells, in 62 primary medullary thyroid carcinomas (MTCs) and in 17 MTCs in tissue from synchronous and/or metachronous lymph node metastases and in one liver metastasis. Sg IV immunoreactivity was present in almost all normal-looking and hyperplastic C-cells, in 59 of 62 (96%) of the primary tumours, in 18 of 26 (69%) lymph node metastases and in distant mestastasis. Sg IV reactivity ranged from small foci of positive tumour cells to a reaction in virtually every malignant cell. Two different staining patterns were obvious: a granular cytoplasmic reactivity and a perinuclear cluster-type signal. Normal-appearing and hyperplastic C-cells were characterized by a uniform granular staining often coexisting with discrete cluster-type immunoreactivity. Various combinations of these staining patterns were observed in C-cell carcinomas. The pure cluster-type reactivity was restricted to malignant C cells and was not detected in normal-appearing and hyperplastic C-cells. In serial sections immunohistochemical results for Sg IV, calcitonin (Ct) and chromogranin A (Cg A) showed only partial correlation. Depending on the area of the tumour chosen, immunohistochemical reactivity for Ct and Cg A might not be demonstrated in neoplastic C-cells, while staining for Sg IV was retained. The amout and type of Sg IV reactivity of MTCs was not correlated with the biological behaviour of the tumours. These results indicate that mAb Hisl-19 is an excellent marker for normal, hyperplastic and neoplastic C-cells. MAb Hisl-19 is especially useful in cases with weak or questionable reactivity for Ct and Cg A. The switch from the granular pattern to the perinuclear distribution seems to indicate a malignant transformation of C-cells and might prove useful as an additional diagnostic clue.     

An immunostaining panel for diagnosis of malignancy in mucinous tumors of the pancreas

BACKGROUND: The diagnosis of malignancy in pancreatic mucinous cystic tumors depends on demonstrating invasion that may be focal and require extensive sectioning. OBJECTIVE: To explore markers that may indicate malignant potential in mucinous cystic tumors. DESIGN: Routinely processed sections from resected specimens of 12 normal pancreata, 14 pancreata with chronic pancreatitis, 9 mucinous cystic tumors, and 30 invasive adenocarcinomas were immunostained with antibodies to p53, HER-2/neu, epithelial growth factor receptor (EGFR), transforming growth factor alpha (TGF-alpha), and Ki-67. RESULTS: Expression of p53, HER-2/neu, and Ki-67 was significantly more frequent in mucinous tumors than in normal pancreatic tissue and chronic pancreatitis tissue (P =.0003 to.05). Strong expression (more than one third of cells positive) and strong intensity (2+ and 3+) of staining of p53 and EGFR were seen only in carcinomas. Coexpression of p53/HER-2/neu and EGFR/HER-2/neu and a frequency of Ki-67+ nuclei of greater than 5% of cells discriminated between mucinous tumors and normal pancreatic tissue and chronic pancreatitis tissue. p53 expression was significantly more frequent in carcinomas than in mucinous tumor (P =.0326). Coexpression of p53/EGFR discriminated between mucinous tumors and carcinomas; however, TGF-alpha was not discriminative. CONCLUSIONS: The immunostaining panel of p53, HER-2/neu, Ki-67, and EGFR can be helpful in indicating malignant potential in mucinous tumors of pancreas in routine pathology practice.     

DNA polymerase alpha. An immunohistochemical marker for proliferating cells in normal and neoplastic human tissues.

DNA polymerase alpha is a DNA replicating enzyme expressed in all proliferating cells. This nuclear antigen in paraformaldehyde-postfixed frozen sections of normal, benign, and malignant tissues was identified by the peroxidase-antiperoxidase technique with the use of a mouse monoclonal antibody against bovine/human DNA polymerase alpha. The nuclei of normal proliferating cells were positive. Malignant tumors (n = 95) showed a higher proportion of positive nuclei than did low-grade malignant tumors (n = 7) or benign lesions (n = 67). The number of positive nuclei in squamous cell carcinomas (n = 19) was higher than in adenocarcinomas (n = 45). Eight (18%) adenocarcinomas and all five renal cell carcinomas had less than 10% positive cells, whereas in benign tissues, such as pituitary adenomas, a thymoma, reactive lymphoid lesions, and some benign mammary nodules, more than 10% of nuclei were labeled. In addition, foci of proliferating cells were clearly recognized. DNA polymerase alpha is, therefore, an excellent marker of proliferative activity that provides an approach to analyzing tumor cell heterogeneity not only in fully developed neoplasms, but also in their precursor lesions.     

Immunohistochemical analysis of Ewing''s sarcoma cell surface antigen p30/32MIC2.

Monoclonal antibody (MAb) HBA71, which was raised against Ewing's sarcoma cells, recognizes a cell-surface glycoprotein, p30/32MIC2, that is encoded by the MIC2 gene in the pseudoautosomal region of human chromosomes X and Y. This immunohistochemical study evaluates the specificity and sensitivity of MAb HBA71 for tumor diagnosis. Frozen and paraffin-embedded tissues of more than 300 tumors of diverse histologic type, including more than 100 small round cell tumors of childhood and adolescence, were tested with this MAb by the avidin-biotin immunoperoxidase procedure. The authors found HBA71 immunoreactivity in 61 of 63 Ewing's sarcomas studied and 9 of 11 primitive neuroectodermal tumors and peripheral neuroepitheliomas. HBA71-negative tumors included neuroblastomas (0 of 24), melanomas (0 of 13), an esthesioneuroblastoma, small cell osteosarcomas (0 of 2), a malignant ectomesenchymoma, desmoplastic SRCT (0 of 5), and medulloblastomas (0 of 5). Heterogeneous expression of HBA71 immunostaining was found in some embryonal rhabdomyosarcomas (3 of 14) and astrocytomas (4 of 7), and in a few neuroendocrine tumors (4 of 26), carcinomas (3 of 94), and lymphomas (6 of 30). Because Ewing's sarcomas are consistently HBA71 positive, the authors searched for antigen-positive normal cells that may represent precursors for these tumors; however, no obvious candidate for the elusive cell of origin for Ewing's sarcoma was identified in the normal fetal tissues tested. Their findings indicate that HBA71 is a highly restricted cell-surface antigen of Ewing's sarcomas and primitive neuroectodermal tumors, and immunohistochemistry employing this antibody may be of value in the differential diagnosis of selected small round cell tumors in childhood and adolescence.     

Remarkably high frequency of EGFR expression in breast carcinomas with squamous differentiation

The human epidermal growth factor receptor (EGFR) is reportedly overexpressed in 15-20% of breast carcinomas. EGFR overexpression is associated with reduced survival and is inversely correlated with expression of estrogen receptor (ER). This study assessed EGFR expression in breast carcinomas with squamous differentiation. The immunohistochemical (IHC) expression of EGFR was evaluated in 39 breast carcinomas with squamous differentiation (30 pure squamous, 6 adenosquamous, 3 carcinosarcomas) by use of the pharmDx assay (clone 2-18C9, DakoCytomation). Cases were considered positive if at least 10% of the cells showed 1+ positivity in the squamous component. Squamous differentiation was confirmed with IHC for CK5-6 (clone D5/16B4, DakoCytomation). ER, PR, and HER2 status as well as clinical information regarding treatment and outcome were correlated. As a control, a tissue microarray comprising 280 lymph node positive breast carcinomas was evaluated with the same EGFR assay. The 39 patients ranged in age from 33 to 77 years (mean 52). The tumors measured 1.3-30 cm (mean 4.8). Sentinel or full axillary lymph node dissection was performed in 28 patients. Fourteen patients had positive lymph nodes. At the time of initial diagnosis, 3 patients had distant metastasis. Follow-up was available for 16 patients (mean 45 months). Disease-free survival at 3 years was 70%. Among the 39 tumors 87% (34) were positive for EGFR (p<0.0001). Sixty-nine percent (27 of 39) showed >50% 2+ EGFR staining. EGFR-positive tumor cells (showing squamous morphology) were also found in 1 bone, 1 lung, and 8 of 11 lymph node metastases available for evaluation. All 11 lymph nodes showed squamous differentiation. All but 1 of the EGFR+ tumors examined were ER and PR negative. Six EGFR-positive tumors were HER2 positive. No statistically significant differences in HER2 status, size, lymph node status and disease-free survival were observed between EGFR+ and EGFR- cases, but the number of EGFR-negative tumors was quite small. Nine of 280 (3%) of lymph node-positive invasive carcinomas on the tissue microarray were EGFR+; review of the initial diagnostic slides failed to reveal squamous features in all but 1 of the 9 EGFR+ tumors. Breast carcinomas with squamous differentiation are a distinct subgroup of breast tumors with a very high frequency of EGFR positivity. Breast carcinomas of this type would be ideal candidates for a trial with EGFR inhibitors.